Field of the Invention
The present invention relates to systems and methods for delivering a prosthesis to a desired location in the body of a patient and methods for delivering and implanting a prosthesis. More particularly, the present invention relates to valve introducer systems for deploying heart valve prostheses within a body lumen and to methods of delivering such prostheses to a desired location in the body. The valve introducer system includes an adjustable deployment mechanism with an implantation depth controlling element and depth gauge to facilitate accurate deployment of the heart valve prosthesis.
Background
Currently, the replacement of a deficient cardiac valve is often performed by opening the thorax, placing the patient under extracorporeal circulation, temporarily stopping the heart, surgically opening the heart, excising the deficient valve, and then implanting a prosthetic valve in its place. This procedure generally requires prolonged patient hospitalization, as well as extensive and often painful recovery.
Recently, minimally invasive approaches have been developed to facilitate catheter-based implantation of valve prostheses in the beating heart, intending to obviate the need for the use of classical sternotomy and cardiopulmonary bypass. For example, U.S. Pat. No. 8,016,877 to Seguin et al. illustrates a technique and a device for replacing a deficient heart valve by percutaneous route. An expandable prosthetic valve is compressed about a catheter, inserted inside a lumen within the body, such as the femoral artery, and delivered to a desired location in the heart. Additionally, U.S. Pat. No. 7,914,569 to Nguyen et al. discloses advancing the catheter containing the prosthesis in a retrograde manner through the femoral artery and into the descending aorta, over the aortic arch, through the ascending aorta and inside the defective aortic valve. This procedure can be assisted by fluoroscopic guidance. Once the position of the catheter containing the prosthesis is confirmed, a sheath containing the prosthesis can be moved proximally, allowing the valve prosthesis to self-expand.
However, in certain instances it may still be necessary to use the classic sternotomy technique. It would be desirable though to avoid cardiopulmonary bypass during the procedure while still obtaining accurate positioning of the prosthetic valve.
With regard to implantation of the heart valve prosthesis and the structure of the prosthesis itself, U.S. Pat. No. 7,914,569 to Nguyen et al. describes an exemplary prosthesis for percutaneous transluminal delivery. The heart valve prosthesis can have a self-expanding multi-level frame that supports a valve body with a skirt and plurality of leaflets. The frame can be contracted during percutaneous transluminal delivery and expanded to an hourglass shape upon deployment within the native heart valve.
Other techniques for delivering prosthetic heart valves via a catheter include a transapical approach for aortic valve replacement, typically involving the use of an introducer port, i.e., a large-bore overtube, of a trocar. A crimped, framed valve prosthesis reversibly coupled to a delivery catheter is transcatheterally advanced toward the native valve, where it is either deployed using a balloon catheter, or, alternatively, using a self-expandable system.
The present invention provides valve introducer systems for implanting a heart valve prosthesis through a trans-aortic pathway. The valve introducer includes an adjustable deployment mechanism with a implantation depth controlling element to precisely set the depth a tubular delivery member extends into the body of a patient. By directly accessing the aorta, it is an object of this invention to accurately implant a prosthetic valve without the need for cardiopulmonary bypass, although the disclosed valve introducer systems can also be used with cardiopulmonary bypass.